Rubber chemicals are important chemical materials in the rubber industry, and they play an important role in improving the rubber performance, such as upgrading the rubber quality and increasing the rubber processing level. With the continuous progress in the rubber industry, there is a higher demand for the general quality of rubber chemicals. At present, the rubber chemicals provided in market are generally of powdery or semispherical shape. The dust of powder rubber chemicals are likely to fly in the air, thereby causing loss of the rubber chemicals and imparting adverse effects on the environment.
Currently, a common granulation method for rubber chemicals is the rotary belt condensation granulating process with the following operating principle: utilizing the low melting point (or softening point) characteristics of the material, the molten liquid material is distributed evenly on a steel belt moving at a uniform speed below a special distributing device depending on the viscosity range of the molten material. Meanwhile, under forced cooling of a continuously spraying device provided under the steel belt, the material is cooled and solidified during the movement and transportation procedure, thereby achieving the purpose of continuous granulation and formation. According to the material properties and the intended use, the distribution mode of intermittent drippling, continuous flowing and full-width overflowing may be employed to obtain semisphere, bar and sheet product, respectively. The method has the following defects: 1) the cooling medium removes heat from the molten liquid via the steel belt, and heat is transferred from the molten liquid to the steel belt and then to the cooling medium. So the heat transfer efficiency decreases significantly. Since the main heat transfer mode is heat conduction between the steel belt surface and the cooling medium, the length of steel belt must be prolonged to increase the throughput, resulting in larger facility bulk and lower space utilization efficiency. 2) Since the liquid drops are formed on the steel belt, the resultant granules show a semispherical or flat shape. Although they have some advantages over the powdery rubber chemicals, the semispherical or flat rubber chemicals still have defects. Specifically, some arris of sharp angle are formed at the boundary of spherical surface and flat surface in the granulation process, and they may be broken off by collision during packaging and transportation and the reproduced powders also pollute the environment. In addition, the formed granules are scraped away from the steel belt at the end of steel belt, in which process dust may fly in the air. The presence of fine powders may cause decrease of melting point in partial regions of the rubber chemicals. Also, the fine powders may join together, conglomerate and harden and the wholly or partially hardening of the rubber chemical products makes a large bulk which deteriorates the product quality seriously. Thus, there requires novel form of rubber chemicals which solve the above problems in the field of rubber chemical granulation.